Electrically-heated water boiler



Oct. l, 1929. H. HARGREAVES ELECTRICALLY HEATED WATER BOILER Filed Aug-8, 1928 2 Sheets-Sheet l inv Oct. l, 1929. H. HARGREAvl-:s

ELECTRICALLY HEATED WATER BOILER Filed Aug. 8, 1.928

2 Sheets-Sheet 2 Patented Oct. 1, 1929 UNTED STATES HAROLD HARGREAVES,OF BURNLEY, ENGLAND ELECTRICALLY-HEATED VATER BOILER Application filedAugust 8, 1928, Serial No. 298,220, and in Great Britain September 14,1927.

1,0.. the boiler proper there being a draw-off tap connected towards thebottom of the collecting chamber. Further features are, an improved.Construction of electrical heating structure and an electrically heateddraw-oil l tap both of which can with advantage be combined in astructure where the feed water is supplied direct to the boiling chamberfrom an outside cistern.

The object of my invention is to provide a 2U' simple construction ofelectrically heated boiler suitable for low loading which will give alarge quantity of actually boiling water at one draw, independent ci theuse of preheated eed water, and wherein the water ways are simple andeasily accessible for removal of iur, etc. Provision is also made forthe employment of a more durable type of electrical heating structurethan has hitherto been used in this class of boiler; and for heat- 3o?ing the collecting chamber preferably at the draw-off tap in order tomaintain actual boiling point and to avoid the drop in temperature whichusually occurs due to the cooling p eilect of the draw-off tap. Laggingor Bir heat insulation oi' all hot surfaces is also provided givingincreased eiiiciency.

Previous constructions have usually employed some form of pre-heating abulk sup- A ply of-water for feeding the boiling chamber 40' in order toobtain a large quantity of boiling water. rThis entails somewhatcomplicated water ways and considerable loss of heat, particularly wherethe bulk water is heated by the admixture of boiling water. In thelatter case, excessive fur is also liable to be formed, as the water isboiled a number of times in the course of heating up the bull; water.

According to the invention, feed water is v led direct from an exteriorball tap feed cistern to the boiling chamber which in turn deliversboiling water into a large capacity collecting` chamber, the diameterand height of which can be made suilicient to supply the largestquantity of water required at one draw. An overflow itting connects thetop of the collecting chamber with the ball tap feed cistern. Thisfitting also serves as an outlet for steam from the collecting chamberand also to return water from the collecting chamber to the cistern ifthe current should be left on after the collecting chamber is full. Thedraw-oil tap is preferably fixed to an electrically heated fitting inorder to counteract the coolingeect of the draw-off tap. This Fittingmay also serve to maintain boiling point in the collecting chamber whenthe main electrical heating element is switched oil". The main heatingelements are preferably of the clamp-on type, and are adapted to beitted to the inner walls of a bellshaped chamber fixed to the boilerstructure by a flange. @n removing` the element chamber, all principalsurfaces liable to accumulate fur are exposed 'for cleaning. A gaugeglass may be connected to the collecting chamber to show the amount ofboiling water available at any time for drawing-off. The main heatingelements may be controlled by a 3 heat or simple on and off switch,accord- 'ng to the amount of boiling water required, but a bye-passelement is kept on during the whole time the boiler is in use, in orderto maintain boiling point.

The improvements are hereafter described in detail and with reference tothe accompanying two sheets of drawings, wherein:

Fig. l is a vertical sectional elevation of the boiler structure andtaken on the line Il-H Fig. 2.

Fig. 2 shows a plan view of the boiler structure.

Fig. 8 is a sectional plan of the main heating elements, etc. the viewbeing taken on the line I-I Fig. l.

Fig. 4 is a sectional elevation of the heating structurev for the drawoff tap the same being` taken on the line V-V Fig. 5.

Fig. 5 is an end view of said heating structure for the draw-off tap.

According to my invention I arrange to feed direct to the boilingchamber from an outside supply cistern tted adjacent to the boiler shelland the construct-ion is to this end. The ball tap structure is marked 1and this automatically controls the supply of feed water to the cistern2. The water supplied to the cistern 2 descends by the pipe 3 and elbowunion fitting 4 to the boiling chamber 5 in the top of which is fixedthe expansion pipe 6, the top of which is above the norn level of waterin the feed cistern. The collecting chamber is marked 7 and towards thebottom thereof is fixed the electrically heated fitting S through whichwater passes to the draw-oli1 tap 9. There is an overflow fittingintermediate of the collecting chamber 7 and the feed cistern 2 and 10,10, 10b are respectively the coupling, nuts and nipples of the over-flowfitting and the construction shown facilitates disconnection.

The cylindrical chamber constitutingthe inner wall of the boilerstructure is lettered. 1.1 and it is closed at the top by the cover 12,which may be fixed by a flange. The cylindrical chamber 11 is divided bya conical plate 13 which is fixed to 11 and divides the boiling chamberfrom the collecting chamber 7. The letter 14 denotes a supporting barfor the expansion pipe 6 and is preferably attached by screws 14LBL tolugs 14b fixed to the cylindrical chamber. The external casing islettered 15 and an annular space exists between 11 and 15 which isfitted with heat insulating material such as granulated cork 15a. Acover 15b is provided. 'I he cylindrical chamber 11 is fixed to a flange16 and 17 is another flange which is secured to the iiange 16 by bolts18. The flange 16 extends over the flange 17 and such flange 16 rests onand is secured to a rim 19 by screws 20. rlhe rim 19 is soldered orotherwise fixed to the external casing 15. 21 is a boss preferably castalong with flange 16 and to which the elbow fitting 4 is attached. 22 isthe element chamber which has a considerable number of flat sides and isclosed at the top whilst its lower edge has an inherent rim or flangewhich is clamped between the flange 16 and rino 17 b studs 1S in mannerto make a water tight joint. Each fiat side of the element chamber 22has a heating element 23 clamped to it, common practice being by meansof screws S. clamping pla-tes l? and nuts N. The

' heating elements 23 are preferably connected electrically byE therings 24, 25, 26 to rods 27, 2S, 29, which are fixed in the cover plate30 by means of insulation washers, nuts, etc. in znown fashion and theserods 27, 28 and 29 serve as terminals. According to the arrangementshown, the terminals can be used for 3 heat control, but the internalconnections to the heating elements can be varied to suit requirements.31 is an asbestos or other suitable plate for shielding the cover platefrom the internal heat of the chamber. It will be seen that by removingthe bolts 13, the element chamber 22 and bottom flange 17, etc. can bewithdrawn, leaving the interior of the boiler accessible for cleaning.

The draw-off tap fitting with the tap 9 removed is shown very clearly byFigs. 4 and 5. The boss 32 is soldered or otherwise fixed to internalcasing 11 and is tapered to receive the bolts 33 which clamp thesections 34, 35 to the boss 32 so as to make a water tight joint. 36 arebosses in which are sunk the heads of terminal screws 37. The saidbosses are then filled in with insulating material such as plaster ofParis. 38 is a porcelain former which fits over the tubular section of35. A two-start7 or double thread is formed on the surface of 38 whichis wound with. heating` wire 39. The heating wire is preferably.vdoubled on itself, the middle or bend of the wire being anchored at theopposite end from the terminals, and each end of the wire is brought toone of the terminal screws 37. A grub screw 40 extends through 35 andengages in a corresponding recess in 33, in order to prevent 3S beingturned by the tension of the heating wire. 41 is a tube brazed orotherwise fixed in 34. The device 35 is screw threaded for the nut 42which clamps the end of 41 against the shoulder on Suitable packing isused to produce water-tight joints and 43 are washers of insulatingmaterial between 33 and 41. 44 are insulated wires carrying current toand from 37. 44, 39 and 37 are secured by nuts, insulating washers,etc., as is common practice.

The wires 44 pass through a cut-away portion 45 of the ange 16 and acorresponding hole in the rim 19. The draw olf tap element may beconnected in parallel with one or more of the main heating elements orin series with one or more of the main elements. rlhe main elements maybe wired in series of two or more in order that thicker wire may be usedallowingl a lower working temperature and longer life. The elementchamber 22 may be made deeper to accommodate more elements if desired.

I declare that what I claim is 1. In an electrically heated self-feedingboiler, a boiler structure, a collecting chamber, boiling chamber, anexpansion pipe leading from the boiling chamber to the collecting`chamber, the top of said pipe being located above the normal waterlevel, an eX- terior water supply cistern adjacent to the boilerstructure, automatic controlling means for the supply cistern, and aconnection from the supply cistern to the boiling chamber, the watersupply feeding direct into the boiling chamber.

2. An electrically heated self-feeding boiler comprising a boilerstructure, a collecting chamber therein, a boiling chamber, an uprightexpansion pipe leading from the boiling chamber to the collectingchamber, an exterior water supply cistern in connection with the boilerStructure, automatic valve controlling means for the cistern, a pipeconnection from the exterior water supply cistern and leading to theboiling chamber and an overflow connection between the collectingchamber and the exterior water supply cistern.

3. An electrically heated self-feeding boiler comprising a boilerstructure, an internal boiling chamber, an internal collecting chamber,an upstanding expansion pipe leading to the collecting chamber anddisciarging at a level above the normal water level in the boiler, anexterior water supply cistern in connection with the boiler structure, acontrol valve for said cistern, a pipe connection from the cisternleading into the boiling chamber, and an overflow connection between thecollecting chamber and the exterior water supply cistern all for thepurposes related` 4;. An electrically heated self-feeding voilerconsisting of a boiler structure, a boiling chamber, a collectingchamber above said boiling chamber, an upstanding expansion pipe leadingfrom the boiling chamber to the upper part of the collecting chamber andhaving its discharge orifice above the normal water level, an exteriorwater supply cistern, automatic control means for the supply cistern, aconnection from the supply cistern to the boiling chamber, and a heatingdevice located in the collecting chamber for raising the temperature ofthe Water in the collecting chamber.

5. An electrically heated self-feeding boiler consisting` of a boiler'structure, a boiling chamber, a collecting chamber above said boilingchamber, an expansion pipe connecting the boiling chamber with thecollecting chamber', said expansion pipe discharging above the normalWater level in the boiler,` an exterior water supply cistern adjacent tothe boiler structure, automatic control means for the supply cistern, aconnection therefrom to the boiling chamber, an electrically heateddevice for the collecting chamber, and a draw-oft1 tap combinedtherewith all as described.

6. An electrically heated self-feeding boiler comprising a boilerstructure, a collecting chamber, a boiling chamber, an expansion pipe,an exterior water supply cistern adjacent to the boiler structure, acontrol valve therein, a pipe leading from the exterior water supplycistern direct into the boiling chamber, an overflow pipe between theexterior Water supply pipe and the collecting chamber, a removablecasing located in the boiling chamber, heating elements secured theretoand Wiring provision for conveying current to and from the heatingelements, and means permitting the removable casing to be detached.

7 An electrically heated self-feeding boiler comprising a boilerstructure, a collecting chamber, a boiling chamber, an expansion pipe,an exterior water supply cistern connected to the boiler structure, acontrol valve in said cistern, a pipe connecting the said cisterndirectly to the boiling chamber, an overflow connection, removableheating provision located in the boiling chamber, and a sleeve structureprovided in the collecting chamber, electrical heating provisiontherefor, and a withdraw tap in combination with said sleeve structure,all for the purposes related.

8. An electrically heated self-feeding boiler comprising a boilerstructure, a collecting chamber therein, a boiling chamber, an outsidefeed water cistern, valve controlling means therefor, a pipe connectionfrom the feedwater cistern direct to the boiling chamber, an overflowconnection intermediate of the collecting chamber and the feed watercistern, an overflow pipe from the boiling chamber, a removable casinglocated in the boiling chamber, heating elements attached thereto andoutlet connections for the heating current, detachable connections forthe removable casing, and a sleeve structure projecting into thecollecting chamber, means for attaching same, means to electrically heatthe sleeve structure, and a withdraw tap combined with the sleevestructure.

In testimony whereof I have signed my name to this specification.

HAROLD HARGR'EAVES.

